Grate for boilers, furnaces, and the like



May 23, 1944. G. Mmx

GRATE FOR BOILERS, FURNACES AND LIKE Filed NOV. 15, 1941 INVEN TO WGEORGE 6 MARX B JMM $72k M4 ATTQRNEYS Patented May 23, 1944 UNITEDsnares earaur {orrlce GRATE FOR BOILERS, FURNACES, AND THE LIKE GeorgeG. Marx, Detroit, Mich.

Application November 13, 1941, Serial No. 418,933

2 Claims.

The present invention relates to grate structure for boilers, furnacesand the like, and has among it objects a grate structure which willprovide for more efficient combustion, particularly at the outer sidesof the mass of burning fuel.

Another object is a grate structure which will provide, without blowersor other mechanical blast producers, a forced draft of preheated air tosuch outer portions of the fuel.

Still other objects and advantages will readily occur to those skilledin the art upon reference to the following description and theaccompanying drawing in which Figure 1 is a perspective view, with apart broken away, of one of the grate bars.

Figure 2 isa section on line 3-3 of Figure 3 but showing a grate bar inelevation.

Figure 3 is a plan view of a portion of the grate structure.

Figure 4 is a side elevation thereof.

In the drawing, there is shown at I!) a modified form of a grate bar,such as is shown in my prior United States Letters Patent No. 1,925,840,dated September 5, 1933, for Furnace grate, and consisting of a bodyportion ll having notched sides and having slots l2 extending verticallytherethrough.

As in the patented form, these slots l2 form ports of passages extendinglengthwise of the bar, those in the alignment being connected byopenings the cross members It and the end slots being connected byopenings It to chambers l5 formed at the bar ends.

These chambers l5 likewise have opening H5 in their end faces preferablysomewhat larger than the openings I4 and on each side of the trunnionsll with which each bar is provided. Also, as in the patented structure,passing up through each chamber I5 i a passage or slot l8.

A plurality of such bars is used to form a complete grate and these aresupported by means of the trunnions IT in notched grate rests 2!]running longitudinally of the firebox of a furnace structure andsupported on suitable legs 2i or on suitable means at the front and rearof the firebox. Each of the plates 20 is provided with openings 22 oneach side of a notch 23 and normally opposite one of the openings l6.Further, each of the plates 20 is provided with a plurality of brackets25 serving to space the plate from the wall 26 of the firebox and alsoserving to support a plate 21 provided with a plurality of openings 28.

It will be noted that while the grate bars I I are somewhat crowned tofacilitate ash removal when shaking, the side margins of the gratestructure including the plates or bars 21 present a flat surface. Thereason for this arrangement is to facilitate ash removal by means of asuitable slice bar or the like. These portions being stationary andflat, running the bar along over the fiat surface causes the accumulatedash to readily fall through the openings 28 and past the grate bar ends.

In order to provide for working the fire each grate bar is of courseprovided with a suitable arm 30, these being connected with a suitableshaking lever (not shown).

In firing a furnace provided with the present grate structure, thepreferred method is to heap up the fuel at the central area of thefirebed, leaving the edges of the bed relatively thin.

This offers greater resistance to the passage of air in the centralportion and forces a large part to travel longitudinally of the gratebars and travel up through the fire bed near the walls of the firebox;

In traveling lengthwise of the heated grate bars, the air of coursebecomes highly heated and, therefore, providing a more eiiicientcombustion medium, causes a greater portion of the combustion to takeplace adjacent the firebox walls, i. e., adjacent the boiler legs.

Further, with the greater part of the active combustion occurringoutside of the main mass of fuel, distillation and coking of fresh fuelcauses more efficiently the formation of a crust of fuel on the top ofthe main bed, and thereby forces the distillation gases toward the Zoneof combustion at the edge.

It is preferred, therefore, to maintain the fuel bed by adding freshfuel to the central portion of the grate, working the burning fueltoward the sides as the fresh fuel is added. In this fashion, and withthe hot air supplied largely to the sides, most of the combustion takesplace at or near the water leg or furnace wall.

Now having described the invention and the preferred embodiment thereof,it is to be understood that the invention is to be limited, not to thespecific details set forth in the specification, but by the scope of theclaims which follow.

I claim:

1. A grate structure for a furnace consisting of a plurality of gratebars having vertical air channels and having longitudinal air passagesconnected therewith, said passages being open to the ends of said bars,a grate rest for said bars, said grate rest having openings adapted toregister with the open ends of said passages, whereby to providecontinuous air channels from beyond said rest to said vertical airchannels, means for spacing said rest from the side wall of the furnace,and a perforated cover plate for the space so produced.

2. A grate structure for a furnace having sidewalls, said structureincluding a plurality of grate bars each having a plurality of verticalair channels and having air passages extending longitudinally andconnected to said channels, an air 1 chamber in each end of said barsand connected to 0 chambers.

GEORGE G. MARX.

